Draft device for furnaces.



- PATENTED JUNE 18, 1-907. J. T. MAZEY. DRAFT DEVICE PORY'FURNAGES.

APPLICATION FILED APR. 4. 1907.

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JOHN THOMAS MAZEY, OF COVENTRY, ENGLAND.

DRAFT DEVICE FOR FUR NACES.

To all whom it may concern:

Be it known that I, JOHN THoMAs MAZEY, a subject of the King of Great Britain, residing at 49 Widdrington road, Coventry, in the county of Warwick, England, have invented certain new and useful Improvements in Draft Devices for Furnaces; and I do hereby declare the following to be a full, clear,

' and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. I 4

My invention relates to furnaces, the term furnaces being used in a broad enough sense to include stoves, and has for its ob ject to provide an improved device or attachment therefor, especially adapted for application to the doors thereof, for the purpose of effecting a more complete combustion of smoke than hitherto obtainable with prior devices. Such a device not only serves to abate the smoke nuisance, but accomplishes a great savin in fuel. The attachment has the effect of admitting air into the combustion chamber of the fire box, and in so doing produces a series of eddies which set up a spiral rotation of the admitted air and restrain the rush of flame and smoke over the bridge and promote complete combustion of all gases before leaving the furnace.

The improved device is illustrated in the accompanyin drawings, where like characters indicate like parts ,throughout the several views.

Referring to the drawings, Figure 1 is a vertical section taken through a portion of the fire box of the furnace and through the door thereof, to which door my improved draft appliance is attached. Fig. 2 is a detailin elevation, showing the interior of the so-called induction box. Fig. 3 is a detail in elevation, lookin at the outer face of the socalled shutter, s .owing the same removed from the induction box. Fig. 4 is an end 'elevation of the shutter shown in Fig. 3 and Fig. 5 is a front elevation of the furnace door, to which the draft appliance is attached.

Of the parts of the furnace 1, the numeral 2'indicates the rate and the numeral 3 the fire box door, w ich latter is provided with air induction ports 4 adapted to be opened and closed by means of a damper 5 which, as shown, .is usually the pivoted type.

Of the parts of the attachment, the numeral 6 indicates the so-called induction box which is in the form of a bowl-like Specification of Letters Patent.

Application filed April 4, 1907. $erial No. 366,255.

Patented Jane 18,1907.

shell, preferably of cast iron and which, as shown, is secured to the door 3 by means of angle brackets 7. In its most inwardly projected portion, thisbox 6 is provided with a horizontally extended slot 8 that extends approximately from one end to the other t ereof and is formed in its upper and lower edges with notches 9 that preferably set obliquely. The notches 9 in the upper edge 'of the slot 8 are offset or located in a horizon tal direction intermediate of the notches in the lower edge of said slot, and this is done for an important purpose which will be hereinafter noted.

The so-called shutter 10 is secured atits ends'to the end walls of the box 6, and is spaced apart from the inwardly bulged walls of said box. In cross section, this shutter 10 is approximately semi-circular but is provided with a projecting ridge 10 that preferably extends into the slot 8. The said shutter 10 is provided with longitudinally extended slots or air passages 11, located one above and one below its ridge 10 In action, the air passes through the air induction ports 4 in the door 3 into the induction box 6, and passes both above and below the shutter 10 and through the ports or slots 11 thereof, and thence into the furnace through the slot or air passage 8 of the said induction box 6. The effect of the form and arrangement of the parts, and especially of the slot 8 and its notches 9 is to cause the air to eddy or whirl, instead of proceeding in a direct stream over the burning products of combustion in the fire box. Furthermore, the notches 9 in the staggered arrangement produce a spiral motion of the induced air, which further overcomes the tendency of the air to take a direct line of travel over the products of combustion. The air is thus commingled with all of the burning products of combustion and thus insures complete combustion, by affording a sufficient supply of oxygen and by insurin an ample supply of oxygen to all portions of the burning gases within the fire box.

The efficiency of the device has been demonstrated in actual practice and it has been found that it not only. effects'the complete combustion of smoke, but that its use results in great savin of fuel and an increased efliciency of the mace 0r stove to which it is applied. It is especially adapted for application to the fire boxes of large boilers,-such as used in steam generating plants, but is ITO - also efficient for use in connection with stoves and heating furnaces.

What I claim is:

1. In adraft appliance for furnaces, an air induction box adapted for application to the interior of the fire box of the furnace, and having a long induction slot or port provided with notches in its edges, substantially as described.

2. In a furnace, the combination with a fire box door having air induction ports, of an induction box secured to the inner side of said door. and provided with a long induction slot or port provided with notches in its upper and lower edges, the notches in its upper edge being staggered with respect to the notches in its lower edge, substantially as described.

3. In a furnace, the combination with a fire box door having air induction ports, of an induction box 6 applied to the inner face thereof, and provided with an air induction slot or passage 8 having in its upper and lower edges notches 9, the upper notches be ing staggered With respect to the lower notches, and a shutter 10 secured to and located within said draft box 6, with air passages left above and below the same, said shutter having the slots or draft passages 11, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN THOMAS MAZEY. Witnesses:

HERBERT JOHNSON, ALBERT BROWN. 

